1. Field of the Invention
The present invention relates to computer based behavior testing of human subjects and more particularly to such testing which monitors the subject's electrical brain-wave activity using an electroencephalograph (EEG) instrument.
2. Related Art
At the present time, the coordination and information processing capabilities of human subjects may be tested using a computer based system. For example, in one device, the subject is asked to engage in a task in which a display is shown on a video monitor while the subject controls a cursor on the screen by operation of a joy stick (control stick). The subject's test score is then compared with the subject's prior test scores to determine if the subject's ability is impaired. Generally that type of system tests eye-hand coordination, but may also test speed of information capacity, i.e., "channel capacity".
It has been suggested that such computer based systems should be used in place of drug testing, which may require urine and/or blood samples.
The purpose of such testing, for example, may be to determine if the subject is within the range of the subject's own normal behavior or if the subject is impaired; or to test the ability of the subject, assuming the subject is alert, to perform eye-hand coordination tasks of the type exemplified by the test.
The present commercially available systems however only test one mode, for example eye-hand coordination, so that the subject may in fact be at least partially impaired or deficient as to functioning in other modes, but such impairment or deficiency will not be detected by the system.
In U.S. Pat. No. 4,158,920 to Walker, entitled "Method And Apparatus For Testing For Brain-Dysfunction In a Human", a subject is tested for brain dysfunction by performing a primary tasking of centering a light spot on a reference point by moving a control stick. Simultaneously, the subject is presented with a secondary task of moving another control stick in response to high or low auditory tones. The subject's responses are recorded on a graph recorder.
In U.S. Pat. No. 4,515,169 to Ward, entitled "Differential Latency Audiometer", an auditory stimulus is directed against the tympanic membrane of the subject's ear to evoke a brain-stem evoked response (BSER). The subject adjusts a latency control knob on the instrument until the sound image is perceived to be in the center of the subject's head. The difference in the latency time is then computed over a set of trials to determine if the subject's differential latency is within the normal range. The use of topographic mapping of brain electrical activity detection using an EEG instrument is illustrated, for example, in U.S. Pat. No. 4,844,086 to Duffy.